The present invention relates to a key switch and more particularly to a push-button key switch used in communications units, keyboards for data inputting, operating panels, and the likes
Conventionally, a key switch whose light emitting portion of an integrated LED or the like illuminates on pressure of a push button Switch is variously used in communications units, keyboards for data inputting, operating panels, aid the like.
For example, an illuminated push button described in unexamined Japanese Patent Publication No. Hei 11-73838 has an LED and provides a print board on which a wiring pattern is integrated into a base, thus providing for an illuminated push button capable of leading light emitted from a luminous element to a display portion without passing the light through a member manufactured with a sealant Disposed sequentially in a vertical direction on the print board are a silicon cover functioning as a sealant in which a reflect case is integrated and as a movable contact, a reflect case mounted in the silicon cover, a filter fitting with the reflect case and the silicon cover internally, and a lens for covering the above-mentioned elements. The above-mentioned elements are housed in a covering member fixed on the base. Further, the silicon cover has apertures on both upper and lower surfaces, and a conductive portion which contacts the wiring pattern on operation is provided on a lower surface of a corner portion.
On the other hand, in Utility Model Publication No. Hei 4-127929, the construction of a luminous element in a membrane-contact-type keyboard in which a circuit pattern for a luminous element is formed in a spacer of a membrane sheet is disclosed in addition, parts besides an installing portion for the luminous element are subjected to insulation processing, as disclosed, in order to provide for the construction of a luminous element in a membranes contact-type keyboard without requiring a complicated run of a pattern or additional print wiring boards even in the event that the number of luminous elements becomes large.
However, the above-mentioned illuminated push button described in unexamined Japanese Patent Publication No. Hei 11-73838 is composed so as to perform external switch connecting information (an electrical contact) via a connector installed in each button. The connector is required to be installed and soldered on the reverse side of an installed LED, thus causing the problems of cumbersome assembly tasks and lower productivity.
Additionally, for installing the push button, protrusions provided on the base member are composed so as to mate to holes drilled in a board for fixing a plurality of push buttons. In the event of installing a plurality of push buttons, a required number of holes must be drilled in the board for fixing the push buttons. In the event of changing positions of a push button, boards for fixing the push button must be prepared for each disposition of the push button, which causes a problem of having low flexibility in disposing the push button on the print wiring board. Further, a problem also arises in that a high parts count results in high manufacturing costs, because eight parts are required besides the LED to be installed on the print wiring board.
The technology described in Utility Model Publication No. Hei 4-127929 also causes the problems of cumbersome assembly tasks and lower productivity, because the LED must be soldered after installing an LED holder on a substrate disposed on a membrane adjacent surface for each switch unit, and the housing composed to cover the LED is fixed by brackets.
Further, the LED provided in the membrane-contact-type switch is soldered on the substrate and a window for checking whether the light is turned on or off is provided at an upper part of the LED in a key top. While the key top is not depressed, a light emitting surface of the LED is in a state of being buried in the key top, which causes a problem of providing a poor visual recognition for other directions than the upper part of the key top.
Furthermore, a problem arises in that a high parts count results in high manufacturing costs, because six parts are required besides the LED to be installed on the print wiring board.
In view of the foregoing problems and disadvantages of the conventional technology, it is therefore an object of the present invention to provide a key switch capable of providing outstanding productivity because of easy assembly tasks and a low parts count, high degree of flexibility in disposing the key switch on a print wiring board, and advantages in visual recognition from other directions than an upper part of the key top.
In addition to the above-mentioned advantages, it is another object of the present invention to provide a key switch which can be fixed securely on a print wiring board without misregistration when installed and requires no other part for fixing. It is also an object of the present invention to have adjacent key switches be fixed securely in the event of successive installation of the key switches.
Further, it is still another object of the present invention to provide a key switch for enhancing keying life with high reliability.
To achieve the above-mentioned objects, the invention claimed is a key switch comprising a button base, a switch base, a contact rubber, a light emitting portion, an a light conductive lens:
According to the invention claimed, assembly of the key switch can be performed easily and productivity can be improved because conventional installation, soldering, and the like of a connector is not required for each key switch unit. And, only four parts are required besides an LED to be installed on the print wiring board, which realizes lowered parts count and manufacturing costs.
Further, the above-mentioned switch base may be detachable from the above-mentioned print wiring board. By having the switch base be detachable from the print wiring board, higher flexibility in disposing the key switch on the print wiring board is provided and dispositions can be changed easily. Further, a conventional structure for supporting the key switch is not required and costs for developing an operating panel surface to which the present key switch is applied can be cut down.
The key switch may be mountable on the print wiring board by inserting and locking a lug portion protruding from a lower portion of the switch base to a through hole drilled in the print wiring board. Thus, the key switch can be detachable from the print wiring board with a simple composition
The key switch may be registered with respect to the above-mentioned print wiring board by protruding a guide pin at lower portion of the above-mentioned switch base and inserting the guide pin into a fixing hole drilled in the above-mentioned print wiring board.
Registration of the key switch with respect to the print wiring board can be performed by the guide pin of the switch base, which results in avoiding misregistration when installed on the print wiring board.
Switches may be combined firmly to each other even in the event of installing the key switches successively. And, no other part is required for the combination
Adjacent key switches may be engagable to each other by fitting a convex portion protruded from the above-mentioned switch base on one side to a concave portion formed in the above-mentioned switch base on the other side of the above-mentioned key switch. Thus, the key switches adjacent to each other can be combined firmly with a simple composition.
A sliding range of the shaft portion of the above-mentioned button base along a shaft supporting portion of the above-mentioned switch base may be set not shorter than a fixed length. For example, by providing that the sliding range is set at not shorter than eight millimeters, slant of the button base and scoring on a sliding surface during sliding can be suppressed and key life of a thousand times can be ensured.
A lens for leading light emitted from a light emitting diode (LED) may be installed in the above-mentioned print wiring board as a light emitting portion for emitting light to outside the key switch through notches formed on a button depressing surface.
According to the invention, for example, an LED illuminated key switch can be disposed successively with 19-millimeter pitch, because the key switch can singly satisfy an emission of light emitting diode (LED) and a function of electrical contact
A label may be provided removably on a button depressing surface of the above-mentioned button base.
A key cap way also be provided for surrounding the button depressing surface of the button base mountably on the above-mentioned button base.